Method of manufacture of a gear driven shutter ink jet printer

ABSTRACT

This patent describes a method of manufacturing a gear driven shutter ink jet print head wherein an array of nozzles are formed on a substrate utilising planar monolithic deposition, lithographic and etching processes. Multiple ink jet heads are formed simultaneously on a single planar substrate such as a silicon wafer. The print heads can be formed utilising standard VLSI/ULSI processing and can include integrated drive electronics formed on the same substrate. The drive electronics preferably being of a CMOS type. In the final construction, ink can be ejected from the substrate substantially normal to the substrate plane.

CROSS REFERENCES TO RELATED APPLICATIONS

The following Australian provisional patent applications are herebyincorporated by cross-reference. For the purposes of location andidentification, US patent applications identified by their US patentapplication serial numbers (USSN) are listed alongside the Australianapplications from which the US patent applications claim the right ofpriority.

CROSS-REFERENCED US PATENT/PATENT APPLICATION AUSTRALIAN (CLAIMING RIGHTOF PROVISIONAL PATENT PRIORITY FROM AUSTRALIAN APPLICATION No.PROVISIONAL APPLICATION) DOCKET No. PO7991 09/113,060 ART01 PO850509/113,070 ART02 PO7988 09/113,073 ART03 PO9395 09/112,748 ART04 PO801709/112,747 ART06 PO8014 09/112,776, PN 6227648 ART07 PO8025 09/112,750ART08 PO8032 09/112,746 ART09 PO7999 09/112,743 ART10 PO7998 09/112,742ART11 PO8031 09/112,741 ART12 PO8030 091112,740, PN 6196541 ART13 PO799709/112,739, PN 6195150 ART15 PO7979 09/113,053 ART16 PO8015 09/112,738ART17 PO7978 09/113,067 ART18 PO7982 09/113,063 ART19 PO7989 09/113,069ART20 PO8019 09/112,744 ART21 PO7980 09/113,058 ART22 PO8018 09/112,777ART24 PO7938 09/113,224 ART25 PO8016 09/112,804 ART26 PO8024 09/112,805ART27 PO7940 09/113,072 ART28 PO7939 09/112,785 ART29 PO8501 09/112,797,PN 6137500 ART30 PO8500 09/112,796 ART31 PO7987 09/113,071 ART32 PO802209/112,824 ART33 PO8497 09/113,090 ART34 PO8020 09/112,823 ART38 PO802309/113,222 ART39 PO8504 09/112,786 ART42 PO8000 09/113,051 ART43 PO797709/112,782 ART44 PO7934 09/113,056 ART45 PO7990 09/113,059 ART46 PO849909/113,091 ART47 PO8502 09/112,753 ART48 PO7981 09/113,055 ART50 PO798609/113,057 ART51 PO7983 09/113,054 ART52 PO8026 09/112,752 ART53 PO802709/112,759 ART54 PO8028 09/112,757 ART56 PO9394 09/112,758 ART57 PO939609/113,107 ART58 PO9397 09/112,829 ART59 PO9398 09/112,792 ART60 PO93996,106,147 ART61 PO9400 09/112,790 ART62 PO9401 09/112,789 ART63 PO940209/112,788 ART64 PO9403 09/112,795 ART65 PO9405 09/112,749, PN 6289262ART66 PPO959 09/112,784 ART68 PP1397 09/112,783 ART69 PP2370 09/112,781DOT01 PP2371 09/113,052 DOT02 PO8003 09/112,834 Fluid01 PO800509/113,103 Fluid02 PO9404 09/113,101 Fluid03 PO8066 09/112,751, PN6227652 IJ01 PO8072 09/112,787, PN 6213588 IJ02 PO8040 09/112,802, PN6213589 IJ03 PO8071 09/112,803, PN 6231163 IJ04 PO8047 09/113,097, PN6247795 IJ05 PO8035 09/113,099 IJ06 PO8044 09/113,084, PN 6244691 IJ07PO8063 09/113,666, PN 6257704 IJ08 PO8057 09/112,778 IJ09 PO805609/112,779, PN 6220694 IJ10 PO8069 09/113,077, PN 6257705 IJ11 PO804909/113,061, PN 6247794 IJ12 PO8036 09/112,818, PN 6234610 IJ13 PO804809/112,816, PN 6247793 IJ14 PO8070 09/112,772, PN 6264306 IJ15 PO806709/112,819, PN 6241342 IJ16 PO8001 09/112,815, PN 6247792 IJ17 PO803809/113,096, PN 6264307 IJ18 PO8033 09/113,068, PN 6254220 IJ19 PO800209/113,095, PN 6234611 IJ20 PO8068 09/112,808 IJ21 PO8062 09/112,809IJ22 PO8034 09/112,780, PN 6239821 IJ23 PO8039 09/113,083 IJ24 PO804109/113,121, PN 6247796 IJ25 PO8004 09/113,122 IJ26 PO8037 09/112,793IJ27 PO8043 09/112,794 IJ28 PO8042 09/113,128, PN 6293653 IJ29 PO806409/113,127 IJ30 PO9389 09/112,756, PN 6227653 IJ31 PO9391 09/112,755, PN6234609 IJ32 PP0888 09/112,754, PN 6238040 IJ33 PP0891 09/112,811, PN6188415 IJ34 PP0890 09/112,812, PN 6227654 IJ35 PP0873 09/112,813, PN6209989 IJ36 PP0993 09/112,814, PN 6247791 IJ37 PP0890 09/112,764 IJ38PP1398 09/112,765, PN 6217153 IJ39 PP2592 09/112,767 IJ40 PP259309/112,768, PN 6243113 IJ41 PP3991 09/112,807, PN 6283581 IJ42 PP398709/112,806, PN 6247790 IJ43 PP3985 09/112,820, PN 6260953 IJ44 PP398309/112,821, PN 6267469 IJ45 PO7935 09/112,822, PN 6224780 IJM01 PO793609/112,825, PN 6235212 IJM02 PO7937 09/112,826, PN 6280643 IJM03 PO806109/112,827, PN 6284147 IJM04 PO8054 09/112,828, PN 6214244 IJM05 PO80656,071,750 IJM06 PO8055 09/113,108, PN 6267905 IJM07 PO8053 09/113,109,PN 6251298 IJM08 PO8078 09/113,123, PN 6258285 IJM09 PO7933 09/113,114,PN 6225138 IJM10 PO7950 09/113,115 IJM11 PO7949 09/113,129, PN 6299786IJM12 PO8060 09/113,124 IJM13 PO8059 09/113,125, PN 6231773 IJM14 PO807309/113,126, PN 6190931 IJM15 PO8076 09/113,119, PN 6248249 IJM16 PO807509/113,120, PN 6290862 IJM17 PO8079 09/113,221, PN 6241906 IJM18 PO865009/113,116 IJM19 PO8012 09/113,118, PN 6241905 IJM20 PO7948 09/113,117IJM21 PO7951 09/113,113, PN 6231772 IJM22 PO8074 09/113,130, PN 6274056IJM23 PO7941 09/113,110, PN 6290861 IJM24 PO8077 09/113,112, PN 6248048IJM25 PO8058 09/113,087, PN 6306671 IJM26 PO8051 09/113,074 IJM27 PO80456,111,754 IJM28 PO7952 09/113,088, PN 6294101 IJM29 P68046 09/112,771IJM30 PO9390 09/112,769, PN 6264849 IJM31 PO9392 09/112,770, PN 6254793IJM32 PP0889 09/112,798, PN 6235211 IJM35 PP0887 09/112,801 IJM36 PP088209/112,800, PN 6264850 IJM37 PP0874 09/112,799, PN 6258284 IJM38 PP139609/113,098 IJM39 PP3989 09/112,833, PN 6228668 IJM40 PP2591 09/112,832,PN 6180427 IJM41 PP3990 09/112,831, PN 6171875 IJM42 PP3986 091112,830,PN 6267904 IJM43 PP3984 09/112,836, PN 6245247 IJM44 PP3982 091112,835IJM45 PP0895 09/113,102, PN 6231148 IR01 PP0870 09/113,106 IR02 PP086909/113,105, PN 6293658 IR04 PP0887 09/113,104 IR05 PP0885 09/112,810IR06 PP0884 09/112,766 IR10 PP0886 09/113,085, PN 6238111 IR12 PP087109/113,086 IR13 PP0876 09/113,094 IR14 PP0877 09/112,760 IR16 PP087809/112,773, PN 6196739 IR17 PP0879 09/112,774 IR18 PP0883 09/112,775, PN6270182 IR19 PP0880 6,152,619 IR20 PP0881 09/113,092 IR21 PO80066,087,638 MEMS02 PO8007 09/113,093 MEMS03 PO8008 09/113,062 MEMS04PO8010 6,041,600 MEMS05 PO8011 09/113,082, PN 6299300 MEMS06 PO79476,067,797 MEMS07 PO7944 09/113,080, PN 6286935 MEMS09 PO7946 6,044,646MEMS10 PO9393 09/113,065 MEMS11 PP0875 09/113,078 MEMS12 PP089409/113,075 MEMS13

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

FIELD OF THE INVENTION

The present invention relates to the manufacture of ink jet print headsand, in particular, discloses a method of manufacture of a Gear DrivenShutter Ink Jet Printer.

BACKGROUND OF THE INVENTION

Many ink jet printing mechanisms are known. Unfortunately, in massproduction techniques, the production of ink jet heads is quitedifficult. For example, often, the orifice or nozzle plate isconstructed separately from the ink supply and ink ejection mechanismand bonded to the mechanism at a later stage (Hewlett-Packard Journal,Vol. 36 no 5, pp33-37 (1985)). These separate material processing stepsrequired in handling such precision devices often add a substantialexpense in manufacturing.

Additionally, side shooting ink jet technologies (U.S. Pat. No.4,899,181) are often used but again, this limits the amount of massproduction throughput given any particular capital investment.

Additionally, more esoteric techniques are also often utilised. Thesecan include electroforming of nickel stage (Hewlett-Packard Journal,Vol. 36 no 5, pp33-37 (1985)), electro-discharge machining, laserablation (U.S. Pat. No. 5,208,604), micro-punching, etc.

The utilisation of the above techniques is likely to add substantialexpense to the mass production of ink jet print heads and therefore addsubstantially to their final cost.

It would therefore be desirable if an efficient system for the massproduction of ink jet print heads could be developed.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an alternative formof ink jet printing which relies upon a gear driven shutter mechanism toblock or allow the ejection of ink from a nozzle chamber.

In accordance with a first aspect of the present invention, there isprovided a method of manufacturing a_print head wherein an array ofnozzles are formed on a substrate utilising planar monolithicdeposition, lithographic and etching processes. Preferably, multiple inkjet heads are formed simultaneously on a single planar substrate such asa silicon wafer.

The print heads can be formed utilising standard vlsi/ulsi processingand can include integrated drive electronics formed on the samesubstrate. The drive electronics preferably being of a CMOS type. In thefinal construction, ink can be ejected from the substrate substantiallynormal

BRIEF DESCRIPTION OF THE DRAWINGS

Notwithstanding any other forms which may fall within the scope of thepresent invention, preferred forms of the invention will now bedescribed, by way of example only, with reference to the accompanyingdrawings, in which:

FIG. 1 is a cut-out top perspective view of the ink nozzle in accordancewith the preferred embodiment of the present invention;

FIG. 2 is an exploded perspective view illustrating the shuttermechanism in accordance with the preferred embodiment of the presentinvention;

FIG. 3 is a top cross-sectional perspective view of the ink nozzleconstructed in accordance with the preferred embodiment of the presentinvention;

FIG. 4 provides a legend of the materials indicated in FIGS. 5 to 18;

FIG. 5 shows a sectional side view of an initial manufacturing step ofan ink jet print heat nozzle showing a silicon wafer layer and a buried,boron doped silicon layer;

FIG. 6 shows a step of depositing a first sacrificial layer in apreviously etched nozzle chamber in the silicon wafer layer;

FIG. 7 shows a step of depositing and etching a first permanent layer;

FIG. 8 shows a step of depositing and etching a second sacrificiallayer;

FIG. 9 shows a step of depositing and etching a second permanent layer;

FIG. 10 shows a step of depositing and etching a third sacrificiallayer;

FIG. 11 shows a step of depositing and etching a first metal layer;

FIG. 12 shows a step of depositing and etching a fourth sacrificiallayer;

FIG. 13 shows a step of depositing and etching a dielectric layer;

FIG. 14 shows a step of back etching the silicon wafer layer;

FIG. 15 shows a step of etching the boron doped silicon layer;

FIG. 16 shows a step of further etching the boron doped silicon layer;

FIG. 17 shows a step of detaching chip from glass blank;

FIG. 18 shows a step of etching the sacrificial layers; and

FIG. 19 shows a step of filling the completed ink jet nozzle with ink.

DESCRIPTION OF PREFERRED AND OTHER EMBODIMENTS

In the preferred embodiment, an ink jet nozzle chamber is providedhaving a shutter mechanism which open and closes over a nozzle chamber.The shutter mechanism includes a ratcheted drive which slides open andclose. The ratcheted drive is driven by a gearing mechanism which inturn is driven by a drive actuator which is activated by passing anelectric current through the drive actuator in a magnetic field. Theactuator force is “geared down” so as to drive a ratchet and pawlmechanism to thereby open and shut the shutter over a nozzle chamber.

Turning to FIG. 1, there is illustrated a single nozzle arrangement 10as shown in an open position. The nozzle arrangement 10 includes anozzle chamber 12 having an anisotropic <111> crystallographic etchedpit which is etched down to what is originally a boron doped buriedepitaxial layer 13 which includes a nozzle rim 14 and a nozzle ejectionport 15 which ejects ink. The ink flows in through a fluid passage 16when the aperture 16 is open. The ink flowing through passage 16 flowsfrom an ink reservoir which operates under an oscillating ink pressure.When the shutter is open, ink is ejected from the ink ejection port 15.The shutter mechanism includes a plate 17 which is driven via means ofguide slots 18, 19 to a closed position. The driving of the nozzle plateis via a latch mechanism 20 with the plate structure being kept in acorrect path by means of retainers 22 to 25.

The nozzle arrangement 10 can be constructed utilising a two level polyprocess which can be a standard micro-electro mechanical systemproduction technique (MEMS). For a general introduction to amicro-electro mechanical system (MEMS) reference is made to standardproceedings in this field including the proceedings of the SPIE(International Society for Optical Engineering), volumes 2642 and 2882which contain the proceedings for recent advances and conferences inthis field. The plate 17 can be constructed from a first levelpolysilicon and the retainers 22 to 25 can be constructed from a lowerfirst level poly portion and a second level poly portion, as it is moreapparent from the exploded perspective view illustrated in FIG. 2.

The bottom circuit of plate 17 includes a number of pits 27 which areprovided on the bottom surface of plate 17 so as to reduce stictioneffects.

The ratchet mechanism 20 is driven by a gearing arrangement whichincludes first gear wheel 30, second gear wheel 31 and third gear wheel32. These gear wheels 30 to 32 are constructed utilising two level polywhich each gear wheel being constructed around a corresponding centralpivot 35 to 37. The gears 30 to 32 operate to gear down the ratchetspeed with the gears being driven by a gear actuator mechanism 40.

Turning to FIG. 2 there is illustrated an exploded perspective view of asingle nozzle chamber 10. The actuator 40 comprises mainly a coppercircuit having a drive end 42 which engages and drives the cogs 43 ofthe gear wheel 32. The copper portion includes serpentine sections 45,46 which concertina upon movement of the end 42. The end 42 is actuatedby means of passing an electric current through the copper portions inthe presence of a magnetic field perpendicular to the surface of thewafer such that the interaction of the magnetic field and circuit resultin a Lorenz force acting on the actuator 40 so as to move the end 42 todrive the cogs 43. The copper portions are mounted on aluminum disks 48,49 which are connected to lower levels of circuitry on the wafer uponwhich actuator 40 is mounted.

Returning to FIG. 1, the actuator 40 can be driven at a high speed withthe gear wheels 30 to 32 acting to gear down the high speed driving ofactuator 40 so as to drive ratchet mechanism 20 open and closed ondemand. Hence, when it is desired to eject a drop of ink from nozzle 15,the shutter is opened by means of driving actuator 40. Upon the nexthigh pressure part of the oscillating pressure cycle, ink will beejected from the nozzle 15. If no ink is to be ejected from a subsequentcycle, a second actuator 50 is utilised to drive the gear wheel in theopposite direction thereby resulting in the closing of the shutter plate17 over the nozzle chamber 12 resulting in no ink being ejected insubsequent pressure cycles. The pits 27 act to reduce the forcesrequired for driving the shutter plate 17 to an open and closedposition.

Turning to FIG. 3, there is illustrated a top cross-sectional viewillustrating the various layers making up a single nozzle chamber 10.The nozzle chambers can be formed as part of an array of nozzle chambersmaking up a single print head which in turn forms part of an array ofprint head fabricated on a semiconductor wafer in accordance with inaccordance with the semiconductor wafer fabrication techniques wellknown to those skilled in the art of MEMS fabrication and construction.

The bottom boron layer 13 can be formed from the processing step of backetching a silicon wafer utilising a buried epitaxial boron doped layeras the etch stop. Further processing of the boron layer can beundertaken so as to define the nozzle hole 15 which can include a nozzlerim 14.

The next layer is a silicon glass layer 52 which normally sits on top ofthe boron doped layer 13. The silicon glass layer 52 includes ananisotropically etched pit 12 so as to define the structure of thenozzle chamber. On top of the silicon layer 52 is provided a glass layer54 which includes the various electrical circuitry (not shown) fordriving the actuators. The layer 54 is passivated by means of a nitridelayer 56 which includes trenches 57 for passivating the side walls ofglass layer 54.

On top of the passivation layer 56 is provided a first level polysiliconlayer 58 which defines the shutter and various cog wheels. The secondpoly layer 59 includes the various retainer mechanisms and gear wheel31. Next, a copper layer 60 is provided for defining the copper circuitactuator. The copper 60 is interconnected with lower portions of glasslayer 54 for forming the circuit for driving the copper actuator.

The nozzle chamber 10 can be constructed utilising the standard MEMSprocesses including forming the various layers utilising the sacrificialmaterial such as silicon dioxide and subsequently sacrificially etchingthe lower layers away.

Subsequently, wafers that contain a series of print heads can be dicedinto separate print heads and a print head mounted on a wall of an inksupply chamber having a piezoelectric oscillator actuator for thecontrol of pressure in the ink supply chamber. Ink is then ejected ondemand by opening the shutter plate 17 during periods of highoscillation pressure so as to eject ink. The nozzles being actuated bymeans of placing the print head in a strong magnetic field utilisingpermanent magnets or electro-magnetic devices and driving currentthrough the actuators e.g. 40, 50 as required to open and close theshutter and thereby eject drops of ink on demand.

One form of detailed manufacturing process which can be used tofabricate monolithic ink jet print heads operating in accordance withthe principles taught by the present embodiment can proceed utilizingthe following steps:

-   1. Using a double sided polished wafer deposit 3 microns of    epitaxial silicon heavily doped with boron.-   2. Deposit 10 microns of n/n+ epitaxial silicon. Note that the    epitaxial layer is substantially thicker than required for CMOS.    This is because the nozzle chambers are crystallographically etched    from this layer. This step is shown in FIG. 5. FIG. 4 is a key to    representations of various materials in these manufacturing    diagrams. For clarity, these diagrams may not be to scale, and may    not represent a cross section though any single plane of the nozzle.-   3. Crystallographically etch the epitaxial silicon using, for    example, KOH or EDP (ethylenediamine pyrocatechol) 70 using MEMS    Mask 1. This mask defines the nozzle cavity. This etch stops on    <111> crystallographic planes, and on the boron doped silicon buried    layer. This step is shown in FIG. 6.-   4. Deposit 12 microns of low stress sacrificial oxide 71. Planarize    down to silicon using CMP. The sacrificial material temporarily    fills the nozzle cavity. This step is shown in FIG. 7.-   5. Begin fabrication of the drive transistors, data distribution,    and timing circuits using a CMOS process. The MEMS processes which    form the mechanical components of the ink jet are interleaved with    the CMOS device fabrication steps. The example given here is of a 1    micron, 2 poly, 2 metal retrograde P-well process. The mechanical    components are formed from the CMOS polysilicon layers. For clarity,    the CMOS active components are omitted.-   6. Grow the field oxide using standard LOCOS techniques to a    thickness of 0.5 microns. As well as the isolation between    transistors, the field oxide is used as a MEMS sacrificial layer, so    ink jet mechanical details are incorporated in the active area mask.    The MEMS features of this step are shown in FIG. 8.-   7. Perform the PMOS field threshold implant. The MEMS fabrication    has no effect on this step except in calculation of the total    thermal budget.-   8. Perform the retrograde P-well and NMOS threshold adjust implants    using the P-well mask. The MEMS fabrication has no effect on this    step except in calculation of the total thermal budget.-   9. Perform the PMOS N-tub deep phosphorus punchthrough control    implant and shallow boron implant. The MEMS fabrication has no    effect on this step except in calculation of the total thermal    budget.-   10. Deposit and etch the first polysilicon layer. As well as gates    and local connections, this layer includes the lower layer of MEMS    components. This includes the lower layer of gears, the shutter, and    the shutter guide. It is preferable that this layer be thicker than    the normal CMOS thickness. A polysilicon thickness of 1 micron can    be used. The MEMS features of this step are shown in FIG. 8.-   11. Perform the NMOS lightly doped drain (LDD) implant. This process    is unaltered by the inclusion of MEMS in the process flow.-   12. Perform the oxide deposition and RIE etch for polysilicon gate    sidewall spacers. This process is unaltered by the inclusion of MEMS    in the process flow.-   13. Perform the NMOS source/drain implant. The extended high    temperature anneal time to reduce stress in the two polysilicon    layers must be taken into account in the thermal budget for    diffusion of this implant. Otherwise, there is no effect from the    MEMS portion of the chip.-   14. Perform the PMOS source/drain implant. As with the NMOS    source/drain implant, the only effect from the MEMS portion of the    chip is on thermal budget for diffusion of this implant.-   15. Deposit 1 micron of glass 72 as the first interlevel dielectric    and etch using the CMOS contacts mask. The CMOS mask for this level    also contains the pattern for the MEMS inter-poly sacrificial oxide.    The MEMS features of this step are shown in FIG. 9.-   16. Deposit and etch the second polysilicon layer 59. As well as    CMOS local connections, this layer includes the upper layer of MEMS    components. This includes the upper layer of gears and the shutter    guides. A polysilicon thickness of 1 micron can be used. The MEMS    features of this step are shown in FIG. 10.-   17. Deposit 1 micron of glass 73 as the second interlevel dielectric    and etch using the CMOS via 1 mask. The CMOS mask for this level    also contains the pattern for the MEMS actuator contacts.-   18. Metal 1 74 deposition and etch. Metal 1 should be non-corrosive    in water, such as gold or platinum, if it is to be used as the    Lorenz actuator. The MEMS features of this step are shown in FIG.    11.-   19. Third interlevel dielectric deposition 75 and etch as shown in    FIG. 12. This is the standard CMOS third interlevel dielectric. The    mask pattern includes complete coverage of the MEMS area.-   20. Metal 2 79 deposition and etch. This is the standard CMOS metal    2. The mask pattern includes no metal 2 in the MEMS area.-   21. Deposit 0.5 microns of silicon nitride (Si₃N₄) 76 and etch using    MEMS Mask 2. This mask defines the region of sacrificial oxide etch    performed in step 26. The silicon nitride aperture is substantially    undersized, as the sacrificial oxide etch is isotropic. The CMOS    devices must be located sufficiently far from the MEMS devices that    they are not affected by the sacrificial oxide etch. The MEMS    features of this step are shown in FIG. 13.-   22. Mount the wafer on a glass blank 77 and back-etch the wafer    using KOH with no mask. This etch thins the wafer and stops at the    buried boron doped silicon layer. The MEMS features of this step are    shown in FIG. 14.-   23. Plasma back-etch the boron doped silicon layer to a depth of 1    micron using MEMS Mask 3. This mask defines the nozzle rim 74. The    MEMS features of this step are shown in FIG. 15.-   24. Plasma back-etch through the boron doped layer using MEMS Mask    4. This mask defines the nozzle 15, and the edge of the chips. At    this stage, the chips are separate, but are still mounted on the    glass blank. The MEMS features of this step are shown in FIG. 16.-   25. Detach the chips from the glass blank. Strip the adhesive. This    step is shown in FIG. 17.-   26. Etch the sacrificial oxide using vapor phase etching (VPE) using    an anhydrous HF/methanol vapor mixture. The use of a dry etch avoids    problems with stiction. This step is shown in FIG. 18.-   27. Mount the print heads in their packaging, which may be a molded    plastic former incorporating ink channels which supply different    colors of ink 78 to the appropriate regions of the front surface of    the wafer. The package also includes a piezoelectric actuator    attached to the rear of the ink channels. The piezoelectric actuator    provides the oscillating ink pressure required for the ink jet    operation. The package also contains the permanent magnets which    provide the 1 Tesla magnetic field for the Lorenz actuators formed    of metal 1.-   28. Connect the print heads to their interconnect systems.-   29. Hydrophobize the front surface of the print heads.-   30. Fill the completed print heads with ink and test them. A filled    nozzle is shown in FIG. 19. It would be appreciated by a person    skilled in the art that numerous variations and/or modifications may    be made to the present invention as shown in the specific embodiment    without departing from the spirit or scope of the invention as    broadly described. The present embodiment is, therefore, to be    considered in all respects to be illustrative and not restrictive.

The presently disclosed ink jet printing technology is potentiallysuited to a wide range of printing systems including: color andmonochrome office printers, short run digital printers, high speeddigital printers, offset press supplemental printers, low cost scanningprinters, high speed pagewidth printers, notebook computers within-built pagewidth printers, portable color and monochrome printers,color and monochrome copiers, color and monochrome facsimile machines,combined printer, facsimile and copying machines, label printers, largeformat plotters, photograph copiers, printers for digital photographic‘minilabs’, video printers, PhotoCD printers, portable printers forPDAs, wallpaper printers, indoor sign printers, billboard printers,fabric printers, camera printers and fault tolerant commercial printerarrays.

Ink Jet Technologies

The embodiments of the invention use an ink jet printer type device. Ofcourse many different devices could be used. However presently popularink jet printing technologies are unlikely to be suitable.

The most significant problem with thermal ink jet is power consumption.This is approximately 100 times that required for high speed, and stemsfrom the energy-inefficient means of drop ejection. This involves therapid boiling of water to produce a vapor bubble which expels the ink.Water has a very high heat capacity, and must be superheated in thermalink jet applications. This leads to an efficiency of around 0.02%, fromelectricity input to drop momentum (and increased surface area) out.

The most significant problem with piezoelectric ink jet is size andcost. Piezoelectric crystals have a very small deflection at reasonabledrive voltages, and therefore require a large area for each nozzle.Also, each piezoelectric actuator must be connected to its drive circuiton a separate substrate. This is not a significant problem at thecurrent limit of around 300 nozzles per print head, but is a majorimpediment to the fabrication of pagewidth print heads with 19,200nozzles.

Ideally, the ink jet technologies used meet the stringent requirementsof in-camera digital color printing and other high quality, high speed,low cost printing applications. To meet the requirements of digitalphotography, new ink jet technologies have been created. The targetfeatures include:

-   -   low power (less than 10 Watts)    -   high resolution capability (1,600 dpi or more)    -   photographic quality output    -   low manufacturing cost    -   small size (pagewidth times minimum cross section)    -   high speed (<2 seconds per page).

All of these features can be met or exceeded by the ink jet systemsdescribed below with differing levels of difficulty. Forty-fivedifferent ink jet technologies have been developed by the Assignee togive a wide range of choices for high volume manufacture. Thesetechnologies form part of separate applications assigned to the presentAssignee as set out in the table above under the heading CrossReferences to Related Applications.

The ink jet designs shown here are suitable for a wide range of digitalprinting systems, from battery powered one-time use digital cameras,through to desktop and network printers, and through to commercialprinting systems

For ease of manufacture using standard process equipment, the print headis designed to be a monolithic 0.5 micron CMOS chip with MEMS postprocessing. For color photographic applications, the print head is 100mm long, with a width which depends upon the ink jet type. The smallestprint head designed is IJ38, which is 0.35 mm wide, giving a chip areaof 35 square mm. The print heads each contain 19,200 nozzles plus dataand control circuitry.

Ink is supplied to the back of the print head by injection moldedplastic ink channels. The molding requires 50 micron features, which canbe created using a lithographically micromachined insert in a standardinjection molding tool. Ink flows through holes etched through the waferto the nozzle chambers fabricated on the front surface of the wafer. Theprint head is connected to the camera circuitry by tape automatedbonding.

Tables of Drop-on-Demand Ink Jets

Eleven important characteristics of the fundamental operation ofindividual ink jet nozzles have been identified. These characteristicsare largely orthogonal, and so can be elucidated as an elevendimensional matrix. Most of the eleven axes of this matrix includeentries developed by the present assignee.

The following tables form the axes of an eleven dimensional table of inkjet types.

-   -   Actuator mechanism (18 types)    -   Basic operation mode (7 types)    -   Auxiliary mechanism (8 types)    -   Actuator amplification or modification method (17 types)    -   Actuator motion (19 types)    -   Nozzle refill method (4 types)    -   Method of restricting back-flow through inlet (10 types)    -   Nozzle clearing method (9 types)    -   Nozzle plate construction (9 types)    -   Drop ejection direction (5 types)    -   Ink type (7 types)

The complete eleven dimensional table represented by these axes contains36.9 billion possible configurations of ink jet nozzle. While not all ofthe possible combinations result in a viable ink jet technology, manymillion configurations are viable. It is clearly impractical toelucidate all of the possible configurations. Instead, certain ink jettypes have been investigated in detail. These are designated IJ01 toIJ45 which matches the docket numbers in the in the table under theheading Cross References to Related Applications.

Other ink jet configurations can readily be derived from theseforty-five examples by substituting alternative configurations along oneor more of the 11 axes. Most of the IJ01 to IJ45 examples can be madeinto ink jet print heads with characteristics superior to any currentlyavailable ink jet technology.

Where there are prior art examples known to the inventor, one or more ofthese examples are listed in the examples column of the tables below.The IJ01 to IJ45 series are also listed in the examples column. In somecases, a printer may be listed more than once in a table, where itshares characteristics with more than one entry.

Suitable applications for the ink jet technologies include: Homeprinters, Office network printers, Short run digital printers,Commercial print systems, Fabric printers, Pocket printers, Internet WWWprinters, Video printers, Medical imaging, Wide format printers,Notebook PC printers, Fax machines, Industrial printing systems,Photocopiers, Photographic minilabs etc.

The information associated with the aforementioned 11 dimensional matrixare set out in the following tables.

ACTUATOR MECHANISM (APPLIED ONLY TO SELECTED INK DROPS) DescriptionAdvantages Disadvantages Examples Thermal An electrothermal Large forceHigh power Canon Bubblejet bubble heater heats the ink to generated Inkcarrier limited 1979 Endo et al GB above boiling point, Simple to Waterpatent 2,007,162 transferring significant construction Low efficiencyXerox heater-in- heat to the aqueous No moving parts High temperaturespit 1990 Hawkins et ink. A bubble Fast operation required al USP4,899,181 nucleates and quickly Small chip area High mechanicalHewlett-Packard forms, expelling the required for actuator stress TIJ1982 Vaught et ink. Unusual materials al USP 4,490,728 The efficiency ofthe required process is low, with Large drive typically less thantransistors 0.05% of the electrical Cavitation causes energy beingactuntor faliure transformed into Kogation reduces kinetic energy of thebubble formation drop. Large print heads are difficult to fabricatePiezo- A piezoelectric crystal Low power Very large area Kyser et al USPelectric such as lead lanthanum consumption required for actuator3,946,398 zirconate (PZT) is Many ink types Difficult to Zoltan USPelectrically activated, can be used integrate with 3,683,212 and eitherexpands, Fast operation electronics 1973 Stemme shears, or bends to Highefficiency High voltage USP 3,747,120 apply pressure to the drivetransistors Epson Stylus ink, ejecting drops. required Tektronix Fullpagewidth IJ04 printheads impractical due to actuator size Requireselectrical poling in high field strengths during manufacture Electro- Anelectric field is Low power Low maximum Seiko Epson, Usui strictive usedto activate consumption strain (approx. et all JP 253401/96electrostriction in Many ink types 0.01%) IJ04 relaxor materials suchcan be used Large area as lead lanthanum Low thermal required foractuator zirconate titanate expansion due to low strain (PLZT) or leadElectric field Response speed is magnesium niobate strength requiredmarginal (˜10 μs) (PMN). (approx. 3.5 V/μm) High voltage can begenerated drive transistors without difficulty required Does not requireFull pagewidth electrical poling print heads impractical due to actuatorsize Ferro- An electric field is Low power Difficult to IJ04 electricused to induce a phase consumption integrate with transition between theMany ink types electronics antiferroelectric (AFE) can be used Unusualmaterials and ferroelectric (FE) Fast operation such as PLZSnT arephase. Perdvskite (<1 μs) required materials such as tin Relatively highActuators require modified lead longitudinal strain a large arealanthanum zirconate High efficiency titanate (PLZSnT) Electric fieldexhibit large strains of strength of around 3 up to 1% associated V/μmcan be readily with the AFE to FE provided phase transition. Electro-Conductive plates are Low power Difficult to IJ02, IJ04 static separatedby a consumption operate electrostatic plates compressible or fluid Manyink types devices in an dielectric (usually air). can be used aqueousUpon application of a Fast operation environment voltage, the plates Theelectrostatic attract each other and actuator will displace ink, causingnormally need to be drop ejection. The separated from the conductiveplates may ink be in a comb or Very large area honeycomb structure,required to achieve or stacked to increase high forces the surface areaand High voltage therefore the force. drive transistors may be requiredFull pagewidth print heads are not competitive due to actuator sizeElectro- A strong electric field Low current High voltage 1989 Saito etal, static pull is applied to the ink, consumption required USP4,799,068 on ink whereupon Low temperature May be damaged 1989 Miura etal, electrostatic attraction by sparks due to air USP 4,810,954accelerates the ink breakdown Tone-jet towards the print Required fieldmedium. strength increases as the drop size decreases High voltage drivetransistors required Electrostatic field attracts dust Permanent Anelectromagnet Low power Complex IJ07, IJ10 magnet directly attracts aconsumption fabrication electro- permanent magnet, Many ink typesPermanent magnetic displacing ink and can be used magnetic materialcausing drop ejection Fast operation such as Neodymium Rare earthmagnets High efficiency Iron Boron (NdFeB) with a field strength Easyextension required around 1 Tesla can be from single nozzles High localused. Examples are: to pagewidth print currents required Samarium Cobaltheads Copper (SaCo) and magnetic metalization should materials in the beused for long neodymium iron boron electromigration family (NdFeB,lifetime and low NdDyFeBNb, resistivity NdDyFeB, etc) Pigmented inks areusually infeasible Operating temperature limited to the Curietemperature (around 540 K) Soft A solenoid induced a Low power ComplexIJ01, 1J05, IJ08, magnetic magnetic field in a soft consumptionfabrication IJ10, IJ12, IJ14, core magnetic core or yoke Many ink typesMaterials not IJ15, IJ17 electro- fabricated from a can be used usuallypresent in a magnetic ferrous material such Fast operation CMOS fab suchas as electroplated iron High efficiency NiFe, CoNiFe, or alloys such asCoNiFe Easy extension CoFe are required [1], CoFe, or NiFe from singlenozzles High local alloys. Typically, the to pagewidth print currentsrequired soft magnetic material heads Copper is in two parts, whichmetalization should are normally held apart be used for long by aspring. When the electromigration solenoid is actuated, lifetime and lowthe two parts attract, resistivity displacing the ink. Electroplating isrequired High saturation flux density is required (2.0-2.1 T isachievable with CoNiFe [1]) Lorenz The Lorenz force Low power Force actsas a IJ06, IJ11, IJ13, force acting on a current consumption twistingmotion IJ16 carrying wire in a Many ink types Typically, only a magneticfield is can be used quarter of the utilized. Fast operation solenoidlength This allows the High efficiency provides force in a magneticfield to be Easy extension useful direction supplied externally to fromsingle nozzles High local the print head, for to pagewidth printcurrents required example with rare heads Copper earth permanentmetalization should magnets. be used for long Only the currentelectromigration carrying wire need be lifetime and low fabricated onthe print- resistivity head, simplifying Pigmented inks materials areusually requirements. infeasible Magneto- The actuator uses the Many inktypes Force acts as a Fischenbeck, USP striction giant magnetostrictivecan be used twisting motion 4,032,929 effect of materials Fast operationUnusual materials IJ25 such as Terfenoi-D (an Easy extension such asTerfenol-D alloy of terbium, from single nozzles are required dysprosiumand iron to pagewidth print High local developed at the Naval headscurrents required Ordnance Laboratory, High force is Copper henceTer-Fe-NOL). available metalization should For best efficiency, the beused for long actuator shouid be pre- electromigration stressed toapprox. 8 lifetime and low MPa. resistivity Pre-stressing may berequired Surface Ink under positive Low power Requires SiIyerbrook,EPtension pressure is held in a consumption supplementary force 0771 658A2 and reduction nozzle by surface Simple to effect drop related patenttension. The surface construction separation applications tension of theink is No unusual Requires special reduced below the materials requiredin ink surfactants bubble threshold, fabrication Speed maybe causing theink to High efficiency limited by surfactant egress from the nozzle.Easy extension properties from single nozzles to pagewidth print headsViscosity The ink viscosity is Simple Requires Silverbrook., EPreduction locally reduced to construction supplementary force 0771 658A2.and select which drops are No unusual to effect drop related patentto be ejected. A materials required in separation applications viscosityreduction can fabrication Requires special be achieved Easy extensionink viscosity electrothermally with from single nozzles properties mostinks, but special to pagewidth print High speed is inks can beengineered heads difficult to achieve for a 100:1 viscosity Requiresreduction. oscillating ink pressure A high temperature difference(typically 80 degrees) is required Acoustic An acoustic wave is Canoperate Complex drive 1993 Hadimioglu generated and without a nozzlecircuitry et al, EUP 550,192 focussed upon the plate Complex 1993 Elrodet al, drop ejection region. fabrication EUP 572,220 Low efficiency Poorcontrol of drop position Poor control of drop volume Thermo- An actuatorwhich Low power Efficient aqueous IJ03, IJ69, IJ17, elastic relies upondifferential consumption operation requires a IJ15, IJ19, IJ20, bendthermal expansion Many ink types thermal insulator on IJ21, IJ22, IJ23,actuator upon Joule heating is can be used the hot side IJ24, IJ27,IJ28, used. Simple planar Corrosion IJ29, IJ30, IJ31, fabricationprevention can be IJ32, IJ33, IJ34, Small chip area difficult IJ35,IJ36, IJ37, required for each Pigmented inks IJ38, IJ39, IJ40, actuatormay be infeasible, IJ41 Fast operation as pigment particles Highefficiency may jam the bend CMOS actuator compatible voltages andcurrents Standard MEMS processes can be used Easy extension from singlenozzles to pagewidth print heads High CTE A material with a very Highforce can be Requires special IJ09, IJ17, IJ18, thermo- high coefficientof generated material (e.g. PTFE) IJ20, IJ21, IJ22, elastic thermalexpansion Three methods of Requires. a PTFE IJ23, IJ24, IJ27, actuator(CTE) such as PTFE deposition are deposition process, IJ28, IJ29, IJ30,polytetrafluoroethylene under development: which is not yet IJ31, IJ42,IJ43, (PTFE) is used. As chemical vapor standard in ULSI IJ44 high CTEmaterials are deposition (CVD), fabs usually non- spin coating, and PTFEdeposition conductive, a heater evaporation cannot be followedfabricated from a PTFE is a with high conductive material is candidatefor low temperatute (above incorporated. A 50 μm dielectric constant350° C.) processing long PTFE bend insulation in ULSI Pigmented inksactuator with Very low power may be infeasible, polysilicon heater andconsumption as pigment particles. 15 mW power input Many ink types naayjam the hend can provide 180 μN can be used actuator force and 10 μmSimple planar deflection. Actuator fabrication motions include: Smallchip area Bend required for each Push actuator Buckle Fast operationRotate High efficiency CMOS compatible voltages and currents Easyextension from single nozzles to pagewidth print heads Conduct- Apolymer with a high High force can be Requires special IJ24 ivecoefficient of thermal generated materials polymer expansion (such asVery low power development (High thermo- PTFE) is doped with consumptionCTE conductive elastic conducting substances Many ink types polymer)actuator to increase its can be used Requires a conductivity to about 3Simple planar deposition process, orders of magnitude fabrication whichis not yet below that of copper, Small chip area standard in ULSI Theconducting required for each fabs polymer expands when actuator PTFEdeposition resistively heated. Fast operation cannot be followedExamples of High efficiency with high conducting dopants CMOStemperature (above include. compatible voltages 350° C.) processingCarbon nanotubes and currents Evaporation and Metal fibers Easyextension CVD deposition Conductive polymers from single nozzlestechniques cannot such as doped to pagewidth print be used polythiopheneheads Pigmented ink Carbon granules may be infeasible, as pigmentparticles may jam the bend actuator Shape A shape memory alloy Highforce is Fatigue limits IJ26 memory such as TiNi (also available(stresses of maximum number alloy known as Nitinol hundreds of MPa) ofcycles Nickel Titanium alloy Large strain is Low strain (1%) developedat the Naval available (more than is required to extend OrdnanceLaboratory) 3%) fatigue resistance is thermally switched High corrosionCycle rate limited between its weak resistance by heat removalmartensitic state and Simple Requires unusual its high stiffnessconstruction materials (TiNi) austenic state. The Easy extension Thelatent heat of shape of the actuator from single nozzles transformationmust in its martensitic state to pagewidth print be provided is deformedrelative to heads High current the austenic shape. Low voltage operationThe shape change operation Requires pre- causes ejection of a stressingto distort drop. the martensitic state Linear Linear magnetic LinearMagnetic Requires unusual IJ12 Magnetic actuators include the actuatorscan be semiconductor Actuator Linear Induction constructed withmaterials such as Actuator (LIA), Linear high thrust, long soft magneticalloys Permanent Magnet travel, and high (e.g. CoNiFe) SynchronousActuator efficiency using Some varieties (LPMSA), Linear planar alsorequire Reluctance semiconductor permanent magnetic Synchronous Actuatorfabrication materials such as (LRSA), Linear techniques Neodymium ironSwitched Reluctance Long actuator horon (NFeB) Actuator (LSRA), andtravel is available Requires complex the Linear Stepper Medium force ismulti-phase drive Actuator (LSA). available circuitry Low voltage Highcurrent operation operation

BASIC OPERATION MODE Description Advantages Disadvantages ExamplesActuator This is the simplest Simple operation Drop repetition Thermalink jet directly mode of operation: the No external fields rate isusually Piezoelectric ink pushes ink acruator directly required limitedto around 10 jet supplies sufficient Satellite drops can kHz. However,this IJ01, IJ02, IJ03, kinetic energy to expel be avoided if drop is notfundamental IJ04, IJ05, IJ06, the drop. The drop velocity is less thanto the method, but is IJ07, IJ09, IJ11, must have a sufficient 4 m/srelated to the refill IJ12, IJ14, IJ16, velocity to overcome Can beefficient, method normally IJ20, IJ22, IJ23, the surface tension.depending upon the used IJ24, IJ25, IJ26, actuator used All of the dropIJ27; IJ28, IJ29, kinetic energy must IJ30, IJ31, IJ32, be provided bythe IJ33, IJ34, IJ35, actuator IJ36, IJ37, IJ38, Satellite drops IJ39,IJ40, IJ41, usually form if drop IJ42, IJ43, IJ44 velocity is greaterthan 4.5 m/s Proximity The drops to be Very simple print Requires closeSilverbrook, EP printed are selected by head fabrication can proximitybetween 0771 658 A2 and some manner (e.g. be used the print head andrelated patent thermally induced The drop the print media orapplications surface tension selection means transfer roller reductionof does not need to May require two pressurized ink). provide the energyprint heads printing Selected drops are required to separate alternaterows of the separated from the ink the drop from the image in the nozzleby nozzle Monolithic color contact with the print print heads are mediumor a transfer difficult roller. Electro- The drops to be Very simpleprint Requires very Silverbrook, EP static pull printed are selected byhead fabrication can high electrostatic 0771 658 A2 and on ink somemanner (e.g. be used field related patent thermally induced The dropElectrostatic field applications surface tension selection means forsmall nozzle Tone-Jet reduction of does not need to sizes is above airpressurized ink). provide the energy breakdown Selected drops arerequired to separate Electrostatic field separated from the ink the dropfrom the may attract dust in the nozzle by a nozzle strong electricfield. Magnetic The drops to be Very simple print Requires magneticSilverbrook, EP pull on ink printed are selected by head fabrication canink 0771 658 A2 and some manner (e.g. be used Ink colors other relatedpatent thermally induced The drop than black are applications surfacetension selection means difficult reduction of does not need to Requiresvery pressurized ink). provide the energy high magnetic fields Selecteddrops are required to separate separated from the ink the drop from thein the nozzle by a nozzle strong magnetic field acting on the magneticink. Shutter The actuator moves a High speed (>50 Moving parts are IJ13,IJ17, IJ21 shutter to block ink kHz) operation can required flow to thenozzle. The be achieved due to Requires ink ink pressure is pulsedreduced refill time. pressure modulator at a mutiple of the Drop timingcan Friction and wear drop ejection be very accurate must be considered.frequency. The actuator Stiction is energy can be very possible lowShuttered The actuator moves a Actuators with Moving parts are IJ08,IJ15, IJ18, grill shutter to block ink small travel can be required IJ19flow through a grill to used Requires ink the nozzle. The shutterActuators with pressure modulator movement need only small force can beFriction and wear be equal to the width used must be considered of thegrill holes. High speed (>50 Stiction is kHz) operation can possible beachieved Pulsed A pulsed magnetic Extremely low Requires an IJ10magnetic field attracts an ‘ink energy operation is external pulsed pullon ink pusher' at the drop possible magnetic field pusher ejectionfrequency. An No heat Requires special actuator controls a dissipationproblems materials for both catch, which prevents the actuator and thethe ink pusher from ink pusher moving when a drop is Complex not to beejected. construction

AUXILIARY MECHANISM (APPLIED TO ALL NOZZLES) Description AdvantagesDisadvantages Examples None The actuator directly Simplicity of Dropejection Most ink jets, fires the ink drop, and construction energy mustbe including there is no external Simplicity of supplied by.piezoelectric and field or other operation individual nozzle thermalbubble. mechanism required. Small physical actuator IJ01, IJ02, IJ03,size IJ04, IJ05, IJ07, IJ09, IJ11, IJ12, IJ24, IJ20, IJ22, IJ23, IJ24,IJ25, IJ26, IJ27, IJ28, IJ29, IJ30, IJ31, IJ32, IJ33, IJ34, IJ35, IJ36,IJ37, IJ38, IJ39, IJ40, IJ41, IJ42, IJ43, IJ44 Oscillating The inkpressure Oscillating ink Requires external Silverbrook, EP inkoscillates, providing pressure can provide ink pressure 0771 658 M andpressure much of the drop a refill pulse, oscillator related patent(including ejection energy. The allowing higher Ink pressure phaseapplications acoustic actuator selects which Operating speed andamplitude must IJ08, IJ13, IJ15, stimul- drops are to be fired Theactuators may be carefully IJ17, IJ18, IJ19, ation) by selectivelyblocking operate with much. controlled IJ21 or enabling nozzles. lowerenergy Acoustic The ink pressure Acoustic lenses reflections in the inkoscillation may be can be used to focus chamber must be achieved byvibrating the sound on the designed for the print head, or nozzlespreferably by an actuator in the ink supply. Media The print head, isLow power Precision Silverbrook, EP proximity placed in close Highaccuracy assembly required 0771 658 A2 and proximity to the print Simpleprint head Paper fibers may related patent medium. Selected constructioncause problems applications drops protrude from Cannot print on theprint head further rough substrates than unselected drops, and contactthe print medium. The drop soaks into the medium fast enough to causedrop separation. Transfer Drops are printed to a High accuracy BulkySilverbrook, EP roller transfer roller instead Wide range of Expensive0771 658 A2 and of straight to the print print substrates can Complexrelated patent medium. A transfer be used construction applicationsroller can also be used Ink can be dried Tektronix hot for proximitydrop on the transfer roller melt piezoelectric separation. inkjet Any ofthe IJ series Electro- An electric field is Low power Field strengthSilverbrook, EP static used to accelerate Simple print head required for0771 658 A2 and selected drops towards construction separation of smallrelated patent the print medium. drops is near or applications above airTone-Jet breakdown Direct A magnetic field is Low power Requiresmagnetic SilverBrook, EP magnetic used to accelerate Simple print headink 0771 658 A2 and field selected drops of construction Requires strongrelated patent magnetic ink towards magnetic field applications theprint medium. Cross The print head is Does not require Requires externalIJ06, IJ16 magnetic placed in a constant magnetic materials magnet fieldmagnetic field. The to be integrated in Current densities Lorenz forcein a the print head, may be high, current carrying wire manufacturingresulting in is used to move the process electromigration actuator.problems Pulsed A pulsed magnetic Very low power Complex print IJ10magnetic field is used to operation is possible head construction fieldcyclically attract a Small print head Magnetic paddle, which pushes sizematerials required in on the ink. A small print head actuator moves acatch, which selectively prevents the paddle from moving.

ACTUATOR AMPLIFICATION OR MODIFICATION METHOD Description AdvantagesDisadvantages Examples None No actuator Operational Many actuatorThermal Bubble mechanical simplicity mechanisms have Ink jetamplification is used. insufficient travel, IJ01, IJ02, IJ06, Theactuator directly or insufficient force, IJ07, IJ16, IJ25, drives thedrop to efficiently drive IJ26 ejection process. the drop ejectionprocess Differential An actuator material Provides greater High stressesare Piezoelectric expansion expands more on one travel in a reducedinvolved IJ03, IJ09, IJ17, bend side than on the other. print head areaCare must be IJ18, IJ19, IJ20, actuator The expansion may be taken thatthe IJ21, IJ22, IJ23, thermal, piezoelectric, materials do not IJ24,IJ27, IJ29, magnetostrictive, or delaminate IJ30, IJ31, IJ32, othermechanism. The Residual bend IJ33, IJ34, IJ35, hend actuator convertsresulting from high IJ36, IJ37, IJ38, a high force low traveltemperature or high IJ39, IJ42, IJ43, actuator mechanism to stressduring IJ44 high travel, lower formation force mechanism. Transient Atrilayer bend Very good High stresses are IJ40, IJ41 bend actuator wherethe two temperature stability involved actuator outside layers are Highspeed, as a Care must be identical. This cancels new drop can be takenthat the bend due to ambient fired before heat materials do nottemperature and dissipates delaminate residual stress. The Cancelsresidual actuator only responds stress of formation to transient heatingof one side or the other. Reverse The actuator loads a Better couplingto Fabrication IJ05, IJ11 spring spring. When the the ink complexityactuator is turned off, High stress in the the spring releases. springThis can reverse the force/distance curve of the actuator to make itcompatible with the force/time requirements of the drop ejection.Actuator A series of thin Increased travel Increased Some piezo- stackactuators are stacked. Reduced drive fabrication oelectric ink jets Thiscan be voltage complexity IJ04 appropriate where Increased actuatorsrequire high possibility of short electric field strength, circuits dueto such as electrostatic pinholes and piezoelectric actuators. MultipleMultiple smaller Increases the Actuator forces IJ12, IJ13, IJ18,actuators actuators are used force available from may not add IJ20,IJ22, IJ28, simultaneously to an actuator linearly, reducing IJ42, IJ43move the irk. Each Multiple actuators efficiency actuator need providecan be positioned to only a portion of the control ink flow forcerequired. accurately Linear A linear spring is used Matches low Requiresprint IJ15 Spring to transform a motion travel actuator with head areafor the with small travel and higher travel spring high force into arequirements longer travel, lower Non-contact force motion. method ofmotion transformation Coiled A bend actuator is Increases travelGenerally IJ17, IJ21, IJ34, actuator coiled to provide Reduces chip arearestricted to planar IJ35 greater travel in a Planar implementationsreduced chip area. implementations are due to extreme relatively easy tofabrication difficulty fabricate. in other orientations. Flexure Abendactuator has a Simple means of Care must be IJ10, IJ19, IJ33 bend smallregion near the increasing travel of taken not to exceed actuatorfixture point, which a bend actuator the elastic limit in flexes muchmore the flexure area readily than the Stress distribution remainder ofthe is very uneven actuator. The actuator Difficult to flexing iseffectively accurately model converted from an with finite element evencoiling to an analysis angular bend, resulting in greater travel of theactuator tip. Catch The actuator controls a Very low actuator ComplexIJ10 small catch. The catch energy construction either enables or Verysmall Requires external disables movement of actuator size force an inkpusher that is Unsuitable for controlled in a bulk pigmented inksmanner. Gears Gears can be used to Low force, low Moving patts are IJ13increase travel at the travel actuators can required expense ofduration. be used Several actuator Circular gears, rack Can befabricated cycles are required and pinion, ratchets, using standard Morecomplex and other gearing surface MEMS drive electronics methods can beused. processes Complex construction Friction, friction, and wear arepossible Buckle A buckle plate can be Very fast Must stay within S.Hirata et al, plate used to change a slow movement elastic limits of the“An Ink-jet Head actuator into a fast achievable materials for longUsing Diaphragm motion. It can also device life Microactuator”, converta high force, High stresses Proc. IEEE MEMS, low travel actuator intoinvolved Feb. 1996, pp 418- a high travel, medium Generally high 423.force motion. power requirement IJ18, IJ27 Tapered A tapered magneticLinearizes the Complex IJ14 magnetic pole can increase magneticconstruction pole travel at the expense force/distance curve of force.Lever A lever and fulcrum is Matches low High stress IJ32, IJ36, IJ37used to transform a travel actuator with around the fulcrum motion withsmall higher travel travel and high force requirements into a motionwith Fulcrum area has longer travel and lower no linear movement, force.The lever can and can be used for also reverse the a fluid sealdirection of travel. Rotary The actuator is High mechanical Complex IJ28impeller connected to a rotary advantage construction impeller. A smallThe ratio of force Unsuitable for angular deflection of to travel of thepigmented inks the actuator results in a actuator can be rotation of theimpeller matched to the vanes, which push the nozzle requirements inkagainst stationary by varying the vanes and out of the number ofimpeller nozzle. vanes Acoustic A refractive or No moving parts Largearea 1993 Hadimioglu lens diffractive (e.g. zone required et aI, EIJP550,192 plate) acoustic lens is Only relevant for 1993 Ekod et al, usedto concentrate acoustic inkjets EIJP 572,220 sound waves. Sharp A sharppoint is used Simple Difficult to Tone-jet conductive to concentrate anconstruction fabricate using point electrostatic field. standard VLSIprocesses for a surface ejecting ink- jet Only relevant forelectrostatic ink jets

ACTUATOR MOTION Description Advantages Disadvantages Examples Volume Thevolume of the Simple High energy is Hewlett-Packard expansion actuatorchanges, construction in the typically required to Thermal Ink jetpushing the ink in case of thermal ink achieve volume Canon Bubblejetall directions. jet expansion. This leads to thermal stress, cavitation,and kogation in thermal ink jet implementations Linear, The actuatormoves in Efficient coupling High fabrication IJ01, IJ02, IJ04, normal toa direction normal to to ink drops ejected complexity may be IJ07, IJ11,IJ14 chip the print head surface. normal to the required to achievesurface The nozzle is typically surface perpendicular in the line ofmotion movement. Parallel to The actuator moves Suitable for FabricationIJ12, IJ13, IJ15, chip parallel to the print planar fabricationcomplexity IJ33, IJ34, IJ35, surface head surface. Drop Friction IJ36ejection may still be Stiction normal to the surface. Membrane Anactuator with a The effective area Fabrication 1982 Howkins push highforce but small of the actuator complexity USP 4,459,601 area is used topush a becomes the Actuator size stiff membrane that is membrane areaDifficulty of in contact with the ink. integration in a VLSI processRotary The actuator causes Rotary levers may Device IJ05, IJ08, IJ13,the rotation of some be used to increase complexity IJ28 element, such agrill travel May have friction or impeller Small chip area at a pivotpoint requirements Bend The actuator bends A very small Requires the1970 Kyser et al when energized. This change in actuator to be made USP3,946,398 may be due to dimensions can be from at least two 1973 Stemmedifferential thermal converted to a large distinct layers, or to USP3,747,120 expansion, motion. have a thermal IJ03, IJ09, IJ10,piezoelectric difference across the IJ19, IJ23, IJ24, expansion,actuator IJ25, IJ29, IJ30, magnetostriction, or IJ31, IJ33, IJ34, otherform of relative IJ35 dimensional change. Swivel The actuator swivelsAllows operation Inefficient IJ06 around a central pivot. where the netlinear coupling to the ink This motion is suitable force on the paddlemotion where there are is zero opposite forces Small chip area appliedto opposite requirements sides of the paddle, e.g. Lorenz force.Straighten The actuator is Can be used with Requires careful IJ26, IJ32normally bent, and shape memory balance of stresses straightens whenalloys where the to ensure that the energized. austenic phase isquiescent bend is planar accurate Double The actuator bends in Oneactuator can Difficult to make IJ36, IJ37, IJ38 bend one direction whenbe used to power the drops ejected by one element is two nozzles. bothbend directions energized, and bends Reduced chip identical. the otherway when size. A small efficiency another element is Not sensitive toloss compared to energized. ambient temperature equivalent single bendactuators. Shear Energizing the Can increase the Not readily 1985Fishbeck actuator causes a shear effective travel of applicable to otherUSP 4,584,590 motion in the actuator piezoelectric actuator material.actuators mechanisms Radial The actuator squeezes Relatively easy toHigh force 1970 Zoltan USP con- an ink reservoir, fabricate singlerequired 3,683,212 striction forcing ink from a nozzles from glassInefficient constricted nozzle. tubing as Difficult to macroscopicintegrate with VLSI structures processes Coil/ A coiled actuator Easy tofabricate Difficult to IJ17, IJ21, IJ34, uncoil uncoils or coils more asa planar VLSI fabricate for non- IJ35 tightly. The motion of processplanar devices the free end of the Small area Poor out-of-plane actuatorejects the ink. required, therefore stiffness low cost Bow The actuatorbows (or Can increase the Maximum travel IJ16, IJ18, IJ27 buckles) inthe middle speed of travel is constrained when energized. MechanicallyHigh force rigid required Push-Pull Two actuators control The structureis Not readily IJ18 a shutter. One actuator pinned at both ends,suitable for ink jets pulls the shutter, and so has a high out-of- whichdirectly push the other pushes it. plane rigidity the ink Curl A set ofactuators curl Good fluid flow Design IJ20, IJ42 inwards inwards toreduce the to the region behind complexity volume of ink that theactuator they enclose. increases efficiency Curl A set of actuators curlRelatively simple Relatively large IJ43 outwards outwards, pressurizingconstruction chip area ink in a chamber surrounding the actuators, andexpelling ink from a nozzle in the chamber. Iris Multiple vanes encloseHigh efficiency High fabrication IJ22 a volume of ink. These Small chiparea complexity simultaneously rotate, Not suitable for reducing thevolume pigmented inks between the vanes. Acoustic The actuator vibratesThe actuator can Large area 1993 Hadimioglu vibration at a highfrequency. be physically distant required for efficient et al, EUP550,192 from the ink operation at useful 1993 Elrod et al, frequenciesEUP 572,220 Acoustic coupling and crosstalk Complex drive circuitry Poorcontrol of drop volume and position None In various ink jet No movingparts Various other Silverbrook, EP designs the actuator tradeoffs are0771 658 A2 and does not move. required to eliminate related patentmoving parts applications Tone-jet

NOZZLE REFILL METHOD Description Advantages Disadvantages ExamplesSurface This is the normal way Fabrication Low speed Thermal inkjettension that ink jets are simplicity Surface tension Piezoelectric inkrefilled. After the Operational force relatively jet actuator isenergized, simplicity small compared to IJ01-IJ07, IJ10- it typicallyreturns actuator force IJ14, IJ16, IJ20, rapidly to its normal Longrefill time IJ22-IJ45 position. This rapid usually dominates returnsucks in air the total repetition through the nozzle rate opening. Theink surface tension at the nozzle then exerts a small force restoringthe meniscus to a minimum area. This force refills the nozzle. ShutteredInk to the nozzle High speed Requires common IJ08, IJ13, IJ15,oscillating chamber is provided at Low actuator ink pressure IJ17, IJ18,IJ19, ink a pressure that energy, as the oscillator IJ21 pressure.oscillates at twice the actuator need only May not be drop ejection openor close the suitable for frequency. When a shutter, instead ofpigmented inks drop is to be ejected, ejecting the ink drop the shutteris opened for 3 half cycles: drop ejection, actuator return, and refill.The shutter is then closed to prevent the nozzle chamber emptying duringthe next negative pressure cycle. Refill After the main actuator Highspeed, as the Requires two IJ09 actuator has ejected a drop a nozzle isactively independent second (refill) actuator refilled actuators per isenergized. The refill nozzle actuator pushes ink into the nozzlechamber. The refill actuator returns slowly, to prevent its return fromemptying the chamber again. Positive The ink is held a slight Highrefill rate, Surface spill must Silverbrook, EP ink positive pressure.therefore a high be prevented 0771 658 A2 and pressure After the inkdrop is drop repetition rate Highly related patent ejected, the nozzleis possible hydrophobic print applications chamber fills quickly headsurfaces are Alternative for:, as surface tension and requiredIJ01-IJ07, IJ10- ink pressure both IJ14, IJ16, IJ20, operate to refillthe IJ22-IJ45 nozzle.

METHOD OF RESTRICTING BACK-FLOW THROUGH INLET Description AdvantagesDisadvantages Examples Long inlet The ink inlet channel Designsimplicity Restricts refill rate Thermal ink jet channel to the nozzlechamber Operational May result in a Piezoelectric ink is made long andsimplicity relatively large chip jet relatively narrow, Reducescrosstalk area IJ42, IJ43 relying on viscous Only partially drag toreduce inlet effective back-flow. Positive The ink is under a Dropselection Requires a Silverbtook, EP ink positive pressure, so andseparation method (such as a 0771 658 A2 and pressure that in thequiescent forces can be nozzle rim or related patent state some of theink reduced effective applications drop already protrudes Fast refilltime hydrophobizing, or Possible operation from the nozzle. both) toprevent of the following: This reduces the flooding of the IJ01-IJ07,IJ09- pressure in the nozzle ejection surface of IJ12, IJ14, IJ16,chamber which is the print head. IJ20, IJ22, IJ23- required to eject aIJ34, IJ36-IJ41, certain volume of ink. IJ44 The reduction in chamberpressure results in a reduction in ink pushed out through the inlet.Baffle One or more baffles The refill rate is Design HP Thermal Ink areplaced in the inlet not as restricted as complexity Jet ink flow. Whenthe the long inlet May increase Tektronix actuator is energized, method.fabrication piezoelectric the rapid ink Reduces crosstalk complexity(e.g. ink jet movement creates Tektronix hot melt eddies which restrictPiezoelectric print the flow through the heads). inlet. The slowerrefill process is unrestricted, and does not result in eddies. FlexibleIn this method recently Significantly Not applicable to Canon flapdisclosed by Canon, reduces back-flow most ink jet restricts theexpanding actuator for edge-shooter configurations inlet (bubble) pusheson a thermal ink jet Increased flexible flap that devices fabricationrestricts the inlet. complexity Inelastic deformation of polymer flapresults in creep over extended use Inlet filter A filter is locatedAdditional Restricts refill rate IJ04, IJ12, IJ24, between the ink inletadvantage of ink May result in IJ27, IJ29, IJ30 and the nozzlefiltration complex chamber. The filter has Ink filter may beconstruction a multitude of small fabricated with no holes or slots,additional process restricting ink flow. steps The filter also removesparticles which may block the nozzle. Small inlet The ink inlet channelDesign simplicity Restricts refill rate IJ02, IJ37, IJ44 compared to thenozzle chamber May resulting a to nozzle has a substantially relativelylarge chip smaller cross section area than that of the nozzle, Onlypartially resulting in easier ink effective egress out of the nozzlethan Out of the inlet. Inlet A secondary actuator Increases speed ofRequires separate IJ09 shutter controls the position of the inkjet printrefill actuator and a shutter, closing off head operation drive circuitthe ink inlet when the main actuator is energized. The inlet is Themethod avoids the Back-flow Requires careful IJ01, IJ03, IJ05, locatedproblem of inlet back- problem is design to minimize IJ06, IJ07, IJ10,behind the flow by arranging the eliminated the negative IJ11, IJ14,IJ16, ink- ink-pushing surface of pressure behind the IJ22, IJ23, IJ25,pushing the actuator between paddle IJ28, IJ31, IJ32, surface the inletand the IJ33, IJ34, IJ35, nozzle. IJ36, IJ39, IJ40, IJ41 Part of the Theactuator and a Significant Small increase in IJ07, IJ20, IJ26, actuatorwall of the ink reductions in back- fabrication IJ38 moves to chamberare arranged flow can be complexity shut off so that the motion ofachieved the inlet the actuator closes off Compact designs the inlet.possible Nozzle In some configurations Ink back-flow None related toSilverbrook, EP actuator of ink jet, there is no problem is inkback-flow on 077 1658 A2 and does not expansion or eliminated actuationrelated patent result in movement of an applications ink back- actuatorwhich may Valve-jet flow cause ink back-flow Tonejet through the inlet.

NOZZLE CLEARING METHOD Description Advantages Disadvantages ExamplesNormal All of the nozzles are No added May not be Most ink jet nozzlefired periodically, complexity on the sufficient to displace systemsfiring before the ink has a print head dried ink IJ01, IJ02, IJ03,chance to dry. When IJ04, IJ05, IJ06, not in use the nozzles IJ07, IJ09,IJ10, are sealed (capped) IJ11, IJ12, IJ14, against air. IJ16, IJ20,IJ22, The nozzle firing IJ23, IJ24, IJ25, usually performed IJ26, IJ27,IJ28, during a special IJ29, IJ30, IJ31, clearing cycle, after IJ32,IJ33, IJ34, fast moving the print IJ36, IJ37, IJ38, head to a cleaningIJ39, IJ40, IJ41, station. IJ42, IJ43, IJ44, IJ45 Extra In systems whichheat Can be highly Requires higher Silverbrook, EP power to the ink, butdo not boil effective if the drive voltage for 077 1658 A2 and inkheater it under normal heater is adjacent to clearing related patentsituations, nozzle the nozzle May require applications clearing can belarger drive achieved by over- transistors powering the heater andboiling ink at the nozzle. Rapid The actuator is fired in Does notrequire Effectiveness May be used with: succes- rapid succession. Inextra drive circuits depends IJ01, IJ02, 1303, sion of someconfigurations, on the print head substantially upon IJ04, IJ05, IJ06,actuator this may cause heat Can be readily the configuration of IJ07,IJ09, IJ10, pulses build-up at the nozzle controlled and the ink jetnozzle IJI1, IJ14, IJ16, which boils the ink, initiated by digital IJ20,IJ22, IJ23, clearing the nozzle. In logic IJ24, IJ25, IJ27, othersituations, it may IJ28, IJ29, IJ30, cause sufficient IJ31, IJ32, IJ33,vibrations to dislodge IJ34, IJ36, IJ37, clogged nozzles. IJ38, IJ39,IJ40, IJ41, IJ42, IJ43, IJ44, IJ45 Extra Where an actuator is A simplesolution Not suitable May be used with: power to not normally driven towhere applicable where there is a hard IJ03, IJ09, IJ16, ink the limitof its motion, limit to actuator IJ20, IJ23, IJ24, pushing nozzleclearing may be movement IJ25, IJ27, IJ29, actuator assisted byproviding IJ30, IJ31, IJ32, an enhanced drive IJ39, IJ40, IJ41, signalto the actuator. IJ42, IJ43, IJ44, IJ45 Acoustic An ultrasonic wave is Ahigh nozzle High IJ08, IJ13, IJ15, resonance applied to the ink clearingcapability implementation cost IJ17, IJ18, IJ19, chamber. This wave iscan be achieved if system does not IJ21 of an appropriate May be alreadyinclude an amplitude and implemented at very acoustic actuator frequencyto cause low cost in systems sufficient force at the which alreadynozzle to clear include acoustic blockages. This is actuators easiest toachieve if the ultrasonic wave is at a resonant frequency of the inkcavity. Nozzle A microfabricated Can clear severely AccurateSilverbrook, EP clearing plate is pushed against clogged nozzlesmechanical 0771 658 A2 and plate the nozzles. The plate alignment isrelated patent has-a-post for every required applications nozzle. A postmoves Moving parts are through each nozzle, required displacing driedink. There is risk of damage to the nozzles Accurate fabrication isrequired Ink The pressure of the ink May be effective Requires pressureMay be, used with pressure is temporarily where other pump or other allIJ series pulse increased so that ink methods cannot be pressureactuator inkjets streams from all of the used Expensive nozzles. Thismay be Wasteful of ink used in conjunction with actuator energizing.Print head A flexible ‘blade' is Effective for Difficult to use if Manyink jet wiper wiped across the print planar print head print headsurface is systems head surface. The surfaces non-planar or very bladeis usually Low cost fragile fabricated from a Requires flexible polymer,e.g. mechanical parts rubber or synthetic Blade can wear elastomer. outin high volume print systems Separate A separate heater is Can beeffective Fabrication Can be used with ink boiling provided at thenozzle where other nozzle complexity many IJ series ink heater althoughthe normal clearing methods jets drop e-ection cannot be used mechanismdoes not Can be require it. The heaters implemented at no do not requireadditional cost in individual drive some inkjet circuits, as manyconfigurations nozzles can be cleared simultaneously, and no imaging isrequired.

NOZZLE PLATE CONSTRUCTION Description Advantages Disadvantages ExamplesElectro- A nozzle plate is Fabrication High temperatures Hewlett Packardformed separately fabricated simplicity: and pressures are Thermal Inkjet nickel from electroformed required to bond nickel, and bonded tonozzle plate the print head chip. Minimum thickness constraintsDifferential thermal expansion Laser Individual nozzle No masks Eachhole must be Canon Bubblejet ablated or holes are ablated by an requiredindividually formed 1988 Sercel et al., drilled intense UV laser in aCan be quite fast Special equipment SPIE, Vol. 998 polymer nozzle plate,which is Some control over required Excimer Beam typically a polymernozzle profile is Slow where there Applications, pp. such as polyimideor possible are many thousands 76-83 polysulphone Equipment of nozzlesper print 1993 Watanabe et required is relatively head al., USP5,208,604 low cost May produce thin burrs at exit holes Silicon Aseparate nozzle High accuracy is Two part K. Bean, IEEE micro- plate ismicromachined attainable construction Transactions on machined fromsingle crystal High cost Electron Devices, silicon, and bonded toRequires Vol. ED-25, No. 10, the print head wafer. precision alignment1978, pp 1185-1195 Nozzles may be Xerox 1990 clogged by adhesive Hawkinset al., USP 4,899,181 Glass Fine glass capillaries No expensive Verysmall nozzle 1970 Zoltan USP capillaries are drawn from glass equipmentrequired sizes are difficult to 3,683,212 tubing. This method Simple tomake form has been used for single nozzles Not suited for makingindividual mass production nozzles, but is difficult to use for bulkmanufacturing of print heads with thousands of nozzles. Monolithic, Thenozzle plate is High accuracy (<1 Requires Silverbrook, EP surfacedeposited as a layer μm) sacrificial layer 0771 658 A2 and micro- usingstandard VLSI Monolithic under the nozzle related patent machineddeposition techniques. Low cost plate to form the applications usingVLSI Nozzles are etched in Existing processes nozzle chamber IJ01, IJ02,IJ04, litho- the nozzle plate using can be used Surface may be IJ11,IJ12, IJ17, graphic VLSI lithography and fragile to the touch IJ18,IJ20, 1322, processes etching. IJ24, IJ27, IJ28, IJ29, IJ30, IJ31, IJ32,IJ33, IJ34, IJ36, IJ37, IJ38, IJ39, IJ40, IJ41, IJ42, IJ43, IJ44Monolithic, The nozzle plate is a High accuracy (<1 Requires long IJ03,IJ05, IJ06, etched buried etch stop in the μm) etch times IJ07, IJ08,IJ09, through wafer. Nozzle Monolithic Requires a IJ10, IJ13, IJ14,substrate chambers are etched in Low cost support wafer IJ15, IJ16,IJ19, the front of the wafer, No differential IJ21, IJ23, IJ25, and thewafer is expansion IJ26 thinned from the back side. Nozzles are thenetched in the etch stop layer. No nozzle Various methods have No nozzlesto Difficult to Ricoh 1995 plate been tried to eliminate become cloggedcontrol drop Sekiya et al USP the nozzles entirely, to positionaccurately 5,412,413 prevent nozzle Crosstalk 1993 Hadimioglu clogging.These problems et al EUP 550,192: include thermal bubble 1993 Elrod etal mechanisms and EUP 572,220 acoustic lens mechanisms Trough Each dropejector has Reduced Drop firing IJ35 a trough through whichmanufacturing direction is sensitive a paddle moves. There complexity towicking. is no nozzle plate. Monolithic Nozzle slit The elimination ofNo nozzles to Difficult to 1989 Saito et al instead of nozzle holes andbecome clogged control drop USP 4,799,068 individual replacement by aslit position accurately nozzles encompassing many Crosstalk actuatorpositions problems reduces nozzle clogging, but increases crosstalk dueto ink surface waves

DROP EJECTION DIRECTION Description Advantages Disadvantages ExamplesEdge Ink flow is along the Simple Nozzles limited to Canon Bubblejet(‘edge surface of the chip, construction edge 1979 Endo et al GBshooter') and ink drops are No silicon etching High resolution is patent2,007,162 ejected from the chip required difficult Xerox heater-in-edge. Good heat sinking Fast color printing pit 1990 Hawkins et viasubstrate requires one print al USP 4,899,181 Mechanically head percolor Tone-jet strong Ease of chip handing Surface Ink flow is along theNo bulk silicon Maximum ink Hewlett-Packard (‘roof surface of the chip,etching required flow is severely TIJ 1982 Vaught et shooter') and inkdrops are Silicon can make restricted al USP 4,490,728 ejected from thechip an effective heat IJ02, IJ11, IJ12, surface, normal to the sinkIJ20, IJ22 plane of the chip. Mechanical strength Through Ink flow isthrough the High ink flow Requires bulk Silverbrook, EP chip, chip, andink drops are Suitable for silicon etching 0771 658 A2 and forwardejected from the front pagewidth print related patent (‘up surface ofthe chip. heads applications shooter') High nozzle IJ04, IJ17, IJ18,packing density IJ24, IJ27-1345 therefore low manufacturing cost Throughink flow is through the High ink flow Requires wafer IJ01, IJ03, IJ05,chip, chip, and ink drops are Suitable for thinning IJ06, IJ07, IJ08,reverse ejected from the rear pagewidth print Requires special IJ09,IJ10, IJ13, (‘down surface of the chip. heads handling during IJ14,IJ15, IJ16, shooter') High nozzle manufacture IJ19, IJ21, IJ23, packingdensity IJ25, IJ26. therefore low manufacturing cost Through Ink flow isthrough the Suitable for Pagewidth print Epson Stylus actuator actuator,which is not piezoelectric print heads require Tektronix hot fabricatedas part of heads several thousand melt piezoelectric the same substrateas connections to drive ink jets the drive transistors. circuits Cannotbe manufactured in standard CMOS fabs Complex assembly required

INK TYPE Description Advantages Disadvantages Examples Aqueous, Waterbased ink which Environmentally Slow drying Most existing ink dyetypically contains: friendly Corrosive jets. water, dye, surfactant, Noodor Bleeds on paper All IJ series ink humectant, and May strikethroughjets biocide. Cockles paper Silverbrook, EP Modern ink dyes have 0771658 A2 and high water-fastness, related patent light fastnessapplications Aqueous, Water based ink which Environmentally Slow dryingIJ02, IJ04, IJ21, pigment typically contains: friendly Corrosive IJ26,IJ27, IJ30 water, pigment, No odor Pigment may clog Silverbrook, EPsurfactant, humectant, Reduced bleed nozzles 0771 658 A2 and andbiocide. Reduced wicking Pigment may clog related patent Pigments havean Reduced actuator applications advantage in reduced strikethroughmechanisms Piezoelectric ink- bleed, wicking and Cockles paper jetsstrikethrough. Thermal ink jets (with significant restrictions) MethylMEK is a highly Very fast drying Odorous All IJ series ink Ethylvolafile solvent used Prints on various Flammable jets Ketone forindustrial printing substrates such as (MEK) on difficult surfacesmetals and plastics such as aluminum cans. Alcohol Alcohol based inkscan Fast drying Slight odor All IJ series ink (ethanol, be used wherethe Operates at sub- Flammable jets 2-butanol, printer must operate atfreezing and temperatures below the temperatures others) freezing pointof Reduced paper water. An example of cockle this is in-camera Low costconsumer photographic printing. Phase The ink is solid at No dryingtime- High viscosity Tektronix hot change room temperature, and inkinstantly freezes Printed ink melt piezoelectric (hot melt) is melted inthe print on the print medium typically has a ink jets head beforejetting. Almost any print ‘waxy' feel 1989 Nowak USP Hot melt inks aremedium can be used Printed pages may 4,820,346 usually wax based, Nopaper cockle ‘block' All IJ series ink with a melting point occurs Inktemperature jets around 80° C. After No wicking may be above the jettingthe ink freezes occurs curie point of almost instantly upon No bleedoccurs permanent magnets contacting the print No strikethrough Inkheaters medium or a transfer occurs consume power roller. Long warm-uptime Oil Oil based inks are High solubility High viscosity: All IJseries ink extensively used in medium for some this is a significantjets offset printing. They dyes limitation for use in have advantages inDoes not cockle ink jets, which improved paper usually require acharacteristics on Does not wick low viscosity. Some paper (especiallyno through paper short chain and wicking or cockle). Oil multi-branchedoils soluble dies and have a sufficiently pigments are required. lowviscosity. Slow drying Micro- A microemulsion is a Stops ink bleedViscosity higher All IJ series ink emulsion stable, self forming Highdye than water jets emulsion of oil, water, solubility Cost is slightlyand surfactant. The Water, oil, and higher than water characteristicdrop size amphiphilic soluble based ink is less than 100 nm, dies can beused High surfactant and is determined by Can stabilize concentrationthe preferred curvature pigment suspensions required (around of thesurfactant. 5%)

1. A method of manufacturing an ink jet printhead which includes:providing a substrate; etching said substrate to form a nozzle chamberof a nozzle; depositing a first sacrificial layer in said nozzlechamber; depositing a plurality of permanent and further sacrificiallayers on the substrate; etching the permanent layers to create ashutter for opening and closing said nozzle chamber and a gear driveassembly in driving engagement with said shutter for opening and closingthe shutter on demand for controlling ejection of ink from a nozzleopening of the nozzle; and removing said sacrificial layers, therebyforming said printhead.
 2. A method of manufacturing an ink jetprinthead as claimed in claim 1 wherein multiple ink jet printheads areformed simultaneously on the substrate.
 3. A method of manufacturing anink jet printhead as claimed in claim 1 wherein said substrate is asilicon wafer.
 4. A method of manufacturing an ink jet printhead asclaimed in claim 1 wherein integrated drive electronics are formed onthe same substrate.
 5. A method of manufacturing an ink jet printhead asclaimed in claim 4 wherein said integrated drive electronics are formedusing a CMOS fabrication process.
 6. A method of manufacturing an inkjet printhead as claimed in claim 1 wherein ink is ejected from saidsubstrate normal to said substrate.
 7. A method of manufacturing an inkjet printhead as claimed in claim 1 which includes fabricating, on thesubstrate, a drive means for driving at least one gear of the gear driveassembly.
 8. A method of manufacturing an ink jet printhead as claimedin claim 7 in which the drive means is a Lorenz force actuator.